On the heels of a public hearing last week in which testimony came overwhelmingly in support of a flat $43 stormwater fee rather than a model that would charge urban and rural property types differently, the Charles County commissioners voted unanimously Tuesday to approve the universal charge.

The fee will pay for a state-mandated stormwater management program that must be implemented by July 1.

Last year, the Maryland General Assembly passed legislation requiring the state’s 10 largest jurisdictions — those that qualify for a National Pollutant Discharge Elimination System permit from the U.S. Environmental Protection Agency — to fund stormwater management projects.

The bill came as part of the state’s efforts to abide by a 2010 order from the EPA requiring states within the Chesapeake Bay watershed to reduce the amount of pollutants they contribute to the estuary.

County staff originally proposed a plan in April that would have set the fee — known colloquially as the “rain tax” — at $32 for urban homeowners, $64 for rural homes and farms, $16 for townhomes and $10.66 for condominiums.

That plan was modified recently to change the respective fees to $30, $60, $15 and $10, while fees for businesses, nonprofits and faith-based groups would have been calculated individually based on each property’s amount of “impervious surface” and could range between $30 and $25,590, according to county figures.

The second option, an alternative proposed by county staff that the commissioners ultimately opted for, will charge a flat $43 fee, essentially a $29 increase to the $14 environmental service fee that currently goes toward stormwater mitigation improvements.

Stormwater runoff is a principle source of Chesapeake Bay pollution, and “impervious surfaces” like structures and asphalt parking lots and driveways, which don’t allow rainwater to soak into the ground, increase runoff.

Environmentalists who criticized the initial proposal as inequitable at a May 1 public hearing were even more dismayed with the alternative at last week’s hearing, but most of the 20 who testified June 12, including representatives of the farming and business communities, supported the flat fee as more fair.

“I think that in a perfect world, it would be more equitable to go with the second rate, but I think the cost of administering it as well as the overwhelming response from the public in support of the flat rate makes me lean towards going in that route,” Commissioner Ken Robinson (D) said.

Rucci said he wanted no inspections conducted on residents’ property, but Associate County Attorney Matthew Clagett said that the state required inspections for property owners who want a credit on their fee or to appeal it altogether. Clagett added that both issues would be mitigated if the commissioners went with the flat fee.

Robinson suggested a future amendment to the program’s rebate provisions, namely that a portion of the $200,000 made available for rebates be allocated to those whose properties are certified as “Bay Wise” by the Maryland Extension Master Gardeners program.

After settling on the flat $43 fee, the commissioners unanimously approved the program’s $2.1 million budget.